class Solution {
public:
    bool lemonadeChange(vector<int>& bills) {
        int five =0,ten=0;
        for(auto x:bills)
        {
            if(x==5) five++;
            else if(x==10)
            {
                if(five==0)return false;
                five--;ten++;
            }
            else
            {
                if(ten && five)
                {
                    ten--;five--;
                }
                else if(five>=3)
                {
                    five-=3;
                }
                else return false;
            }
            
        }
        return true;
    }
};
